<html>
<head>

<script id='vertex' type='x-shader/x-vertex'>
attribute vec3 aCoord;

void main() {
  gl_Position = vec4(aCoord, 1.0);
  gl_PointSize = 1.00 / aCoord.z;
}
</script>

<script id='fragment' type='x-shader/x-fragment'>
precision mediump float;
uniform vec4 uColor;

void main() {
  vec2 coord = gl_PointCoord * 2.0 - vec2(1.0, 1.0);
  float l = 1.0 / length(coord) - 1.0;
  gl_FragColor = uColor * vec4(l, l, l, 1.0);
}
</script>

</head>
</html>

